Many applications, especially for functional safety, require monitoring to make sure that the output current stays close to the programmed value. To monitor the output current, place a sense resistor in series with the output and measure the voltage across the resistor. However, this resistor reduces the compliance voltage available for the load. The DACx750 provide access to an internal precision resistor (R3 in Figure 8-2) through the R3-SENSE and BOOST pins to perform analog readback for monitoring the output current. Measure the voltage between the R3-SENSE and BOOST pins and divide by the value of the R3 resistor to determine the magnitude of the output current. The R3 resistor has a typical value of 40 Ω (see Figure 7-38 for a plot of resistance vs temperature) with a temperature drift coefficient of 40 ppm/°C (see Figure 7-39 for a histogram of R3 resistance temperature drift). The R3 resistor is tested to stay within the minimum (36 Ω) and maximum (44 Ω) resistance values shown in the R3 Resistor portion of Section 7.5. To remove the tolerance error, perform a simple calibration by programming a certain value of output current, measuring the voltage across R3-SENSE and BOOST, and calculating the exact value of R3.